Numerical simulation of the focused powder streams in coaxial laser cladding

The powder flow structures of a coaxial nozzle for laser cladding was simul ated by the numerical programme FLUENT with various arrangements of the noz zle exit. Both focused and columnar powder streams could be generated in a coaxial nozzle. It can be found that the concentration mode is influenced s ignificantly by the nozzle arrangement and gas flow settings. According to the numerical results, more than 50% powder concentration can be increased in a gas stream through a specific nozzle arrangement for coaxial laser cla dding. (C) 2000 Elsevier Science S.A. All rights reserved.